So if I start my car (can be cold from over night or after being off for 30 minutes) it runs rough to the point where I can't drive it at all. The RPM's are bouncing (without any throttle applied) between just above 0 to 1500 or so. The car never stalls and seems to smoothen out after a minute or two, but once I try driving again, it gets rough again.

If I shut off the car and start it right back up, it runs fine as if nothing happened. The SES light is not on.

I borrowed a Peake scanner from a friend and get:
69 - “Engine coolant temperature, Plausibility”

Do you know about the secret OBC menu and tests? Here is a link Gadget Freaks II: Fun you never knew you could have [secret menu] now you need to look at that temp which is listed at ktemp (sorry forget which test) 7? maybe. Tell me the temp before start what it gets to then shut off read temp again before restart and then last the temp when you have it warmed up and are driving around.
Note if the temp bounces around or if stable.

I just did that secret menu test, the Ktemp stays between 88 and 89 celcius at idle after driving the car for about 20 minutes. I'll grab the other readings once I get a chance, popping into a meeting now.

The car is driving ok right now, I'll try to get the readings when it's idling rough.

I also filled up with new gas (I had 1/4 tank left prior) just to make sure it wasn't sucking up dirty gas near the bottom of the tank.

I just did that secret menu test, the Ktemp stays between 88 and 89 celcius at idle after driving the car for about 20 minutes. I'll grab the other readings once I get a chance, popping into a meeting now.

The car is driving ok right now, I'll try to get the readings when it's idling rough.

I also filled up with new gas (I had 1/4 tank left prior) just to make sure it wasn't sucking up dirty gas near the bottom of the tank.

Not sure what your outside temps are, but 88-89C seems a bit high to me for idling after a normal drive. My highway temps generally are in the mid 80's.

Peake code 69 is often a bad tstat. They tend to fail in the open position, so the car runs cold. See how the car runs on the highway, anything below 78-79C generally means tstat needs replacing.

Since the problem goes away with restart, it sounds electrical. That always leads me to check the MAF's (and when you unlock the OBC, you can do the dynamic MAF test, #4, option #2) and the 4 CPS.

Do you know about the secret OBC menu and tests? Here is a link Gadget Freaks II: Fun you never knew you could have [secret menu] now you need to look at that temp which is listed at ktemp (sorry forget which test) 7? maybe. Tell me the temp before start what it gets to then shut off read temp again before restart and then last the temp when you have it warmed up and are driving around.
Note if the temp bounces around or if stable.

Do it one more time when the car has sat over night but that 60c is likely telling you that your temp sender is done. Three hours may not be enough time. The reason the car runs bad is it is trying to start thinking it is warmer than it is. A lot will be adjusted wrong for it to start clean. The car does not believe it either or would not throw the 69 code. If you have not done so you might as well do the T-stat too, they fail, most cars have had them replaced once or twice. It maybe hidden in the faulty temp sender.

Tomorrow morning the ktemp should be the exact same as the outside temp. Best of luck

Do it one more time when the car has sat over night but that 60c is likely telling you that your temp sender is done. Three hours may not be enough time. The reason the car runs bad is it is trying to start thinking it is warmer than it is. A lot will be adjusted wrong for it to start clean. The car does not believe it either or would not throw the 69 code. If you have not done so you might as well do the T-stat too, they fail, most cars have had them replaced once or twice. It maybe hidden in the faulty temp sender.

Tomorrow morning the ktemp should be the exact same as the outside temp. Best of luck

So I let the car sit overnight (about 10 hours). Ambient temperature in the garage was 18 C in the morning (I park underground, no sun factor).

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